Technical Abstract:
Jet cooked starch-lipid composites have been developed as a technology for suspending micron-size lipid droplets in aqueous cooked starch dispersions. Normally oil droplets are independent and freely mobile in such liquid composites. When wheat flour was used as the starch source, unusual behavior of the cooked dispersion was observed suggesting gluten effects on oil droplet distribution. Wheat gluten was shown to form amorphous networks and condense into dense masses when jet cooked alone, but when combined with wheat starch, the gluten networks were suspended in the dispersion. Soy oil droplets were observed to be embedded in the gluten networks in ternary composites with wheat starch and gluten as well as flour-oil composites, and no freely mobile oil droplets were seen. Association of oil droplets with gluten did not occur when mixed together after cooling jet-cooked dispersions. Wheat gluten reduced the size of soy oil droplets in cornstarch-soy oil composites, entrapped all oil droplets into gluten network fragments, and substantially increased the efficiency of oil encapsulation in drum dried composites. These observations explain the unusual behavior of jet-cooked flour-oil composites and enable the design of liquid and dried cornstarch-lipid composites with higher oil content.